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Delusions of Parasitosis, Delusional Infestation, and Morgellons Disease: 3 Names for 1 Disease?

Olivia Hughes, MD

Delusions of parasitosis (DOP) is a term that was first introduced in 1946 to refer to patients who have a fixed, false belief that their skin is infested with parasites such as fleas, ticks, worms, or other organisms.1 It was not until 2003 that the term “Morgellons disease” was introduced and used to refer to patients who believe they have fibers or specks in their skin. Reichenberg et al article presents the idea that patients who report fibers in their skin may differ from those who report bugs. The aim of their study was to identify differences in presentation and clinical course among patients who were referred for a diagnosis of DOP and were found to have a diagnosis of either DOP, a primary medical condition, or other psychiatric disorder.1 The study was a single-center, single-provider retrospective review of patients who were referred with a diagnosis of DOP and seen between 2008 and 2011. Forty-seven patients met inclusion criteria. Two dermatologists and 1 psychiatrist reviewed each patient’s chart focusing on several key data points before making a final diagnosis. Patients completed questionnaires including the Modified Mini Screen for psychiatric disease. Final diagnoses were characterized as DOP (those given a diagnosis of DOP or schizophrenia), Somatic (those given a diagnosis of a somatiform disorder), or Other (picker, obsessive-compulsive disorder, medical diagnosis identified, or no cause identified). The patients’ chief symptoms were significantly associated with having a particular final diagnosis.1 Patients who reported bugs were more likely to have a final diagnosis of delusional disorder or a medical condition, whereas patients who reported seeing fibers were more likely to be diagnosed with a somatiform disorder.1 A patient who reported “infection” was 19 times more likely to have a final diagnosis of DOP compared to a person whose chief symptom was “lesion.” This study found that patients who were referred for a diagnosis of DOP comprised a heterogenous group of people with a variety of final diagnoses.

1. Reichenberg JS, Magid M, Jesser CA, Hall CS. Patients labeled with delusions of parasitosis compose a heterogenous group: A retrospective study from a referral center. J Am Acad Dermatol. 2013;68(1): 41-46. doi:10.1016/j.jaad.2012.08.006


A retrospective chart review of 24 adult patients with Morgellons disease at Weill Cornell Medical College examined the use of low-dose trifluoperazine for the treatment of Morgellons Disease. Of the 24 patients who met inclusion criteria and received treatment with trifluoperazine, 29% experienced at least 90% lesion clearance and 63% experienced at least 50% improvement.1 Only 17% reported minor adverse effects, such as drowsiness. Time to 50% disease control took a mean of 2.4 months, while time to 90% disease control took a mean of 6.6 months. Average dose needed to achieve 50-90% improvement was 1.9 mg per day while the dose needed for greater than 90% clearance was 2.3 mg per day.1 These results are similar to results seen with pimozide and atypical antipsychotics.1 This study demonstrates that trifluoperazine at low doses up to 4 mg per day may have minimal to no adverse effects with good efficacy making it an attractive treatment option for Morgellons disease.

1. Yan BY, Jorizzo JL. Management of Morgellons disease with low-dose trifluoperazine. JAMA Dermatol. 2018;154(2):216-218. doi:10.1001/jamadermatol.2017.5175


Delusional infestation refers to patients who have a fixed false belief that their skin is infested with animate (parasites or bugs) or inanimate (fibers) materials despite objective evidence otherwise.1 This single-center, retrospective study evaluated 147 patients who were seen for delusional infestation between the years 2001 to 2007 in order to review the demographics and clinical presentations of these patients and compare the findings with other published data. In this study, the mean age was 57 years, female-to-male ratio was 2.89:1, 96% were white, and 56% were married.1 Mean duration of symptoms was 31 months and 87% of patients had been seen by another provider prior to seeking treatment at Mayo Clinic. Overall, 33% of patients were self-described as disabled with one-third of those stating it was due to their infestation. Twenty-eight percent of patients were retired, and 26% were employed.1 In addition, 76% of patients gave detailed descriptions of how the infestation began and 67% attempted self-treatment with methods such as kerosene baths, bleach, vinegar, exterminators, moving homes, tweezing or cutting the skin, and burning the skin with lighters. Additionally, 81% of patients had a history of a psychiatric illness with depression, substance abuse, and anxiety being the most common and 26% had a shared psychotic disorder with another person.1 The most common physical exam findings were excoriations, erythema, scars, papules, and postinflammatory hyperpigmentation. Seventy-four percent of these patients were referred for psychiatric evaluation but only half of these patients followed through with the referral. Several of these statistics are consistent with what has been previously reported in the literature including mean age and duration of symptoms.1 Other findings in this study that had not been previously reported or were different from the literature included employment data, a higher percentage were married, and a higher percentage were white.1 This article is unique in that it is one of the few large case series to evaluate both patients who have delusions of parasites and those who have delusions of inanimate objects. Limitations of this study include that it was retrospective in nature and took place at a single center in the Midwest and may not be generalizable. 

1. Foster AA, Hylwa SA, Bury JE, Davis MD, Pittelkow MR, Bostwick JM. Delusional infestation: Clinical presentation in 147 patients seen at Mayo Clinic. J Am Acad Dermatol. 2012;67(4):673.e1-10. doi:10.1016/j.jaad.2011.12.012

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